This invention relates generally to electronic test instruments, particularly digital multimeters having a current sensing clamp. Digital multimeters, or DMM's, are used to measure a variety of electrical parameters, such as AC voltage, DC voltage, resistance and current. Clamp-type DMMs, also known simply as clamp meters, can measure current without interfering with the current carrying conductor. One such clamp meter is described in U.S. patent application Ser. No. 09/774,526, the disclosure of which is hereby incorporated by reference. In addition, clamp meters have the ability to measure fairly high levels of current.
Clamp meters measure current flow in a conductor without having to make electrical connection with the conductors forming the circuit. Instead two clamp jaws having electrical coils embedded therein encircle the conductor and sense the magnetic field created by the current flow in order to measure the current. However, the physical arrangement of the measured conductor in relation to the clamp jaws, housing and display dictates the orientation in which the clamp meter must be used. This can make it difficult to read the display in certain situations.
Typically, clamp meters have an elongated rectangular housing designed to be held in one hand. A pair of clamp jaws extends from the top of the housing. The jaws are situated in a fixed plane that is generally parallel to the plane of the front face of the housing. The meter's display is normally also disposed in the front face of the housing. Accordingly, when the clamp jaws are placed around a conductor the display can be forced into a position which may make reading the display difficult, if not impossible. This occurs most often when the current-carrying conductor is overhead or disposed in tight physical spaces such as an electrical cabinet.
It has been determined that adding a display to the side of a multimeter housing disposed on a plane generally perpendicular to the plane formed by the clamp jaws facilitates the reading of measurements even when the clamp meter is in an awkward position dictated by the need to surround a current-carrying conductor.